1. Field of the Invention
The present invention is an apparatus and method for killing weed pests and soil-borne plant pathogens that does not rely on sunlight or warm weather. More specifically, a top soil is artificially pasteurized thereby rendering the top soil particularly suitable for planting a fresh crop therein.
2. Description of the Related Art
Effective control of soil-borne plant pathogens, and some weed pests is a serious challenge for farmers and home gardeners. Pathogen resistant crop varieties, crop rotation, and pesticides are not always viable control options for these destructive highlight the need for alternative methods of controlling soil-borne pathogens such as nematodes, harmful fungi, and bacteria. Thus, a better way of controlling soil pathogens is required that does not solely rely on herbicides.
Crop rotations provide one alternative to the use of potentially toxic and costly soil pesticides. Soil pests have grown increasingly resistant to the beneficial effects of crop rotations. Crop farmers in general, and particularly small crop farmers, find rigorous adherence to crop rotations over burdensome. Thus, a better way of controlling soil pathogens is needed that does not rely on crop rotations.
Soil solarization based on radiant heat (i.e., infra-red radiation) offers a further alternative to the use of toxic and costly soil pesticides to destroy weeds and thereby improve crop yields (see, e.g., xe2x80x9cSoil Solarization,xe2x80x9d in Environmental Restoration, author: David A. Bainbridge http://www.ecocomposite.org/restoration/soilsolar.htm, three pages). A clear polyethylene mulch or tarp is used to trap solar heat in the soil. Over a period of several weeks to a few months, soil temperatures may become high enough to kill soil pests and weed seed to a depth of about 8 inches. However, crop farmers often find such extended periods over burdensome. In particular, there is always a strong risk that the weather will not cooperate and planting of crops may be delayed and in extreme cases whole planting seasons may be lost. Thus, a better way of controlling weeds is required that does not rely on solar radiation and warm weather.
Several efforts have been made to address these and other problems. U.S. Pat. No. 5,282,695, issued Feb. 1, 1994 to Crosby et al describes an apparatus and method of thermally stripping volatile organic compounds (VOCs) from soil using a recirculating combustible gas. The ""695 apparatus is a transportable thermal stripping system comprising a vessel in which VOC contaminated soil is placed into contact with a hot gas. In a preferred embodiment the temperature of the hot air is maintained in the range of 800xc2x0 to 1500xc2x0 F. which has more of a sterilization effect than a pasteurization effect. Thus, the ""695 expressly teaches away from the present invention wherein improved crop yields are obtained by pasteurizing a top soil.
U.S. Pat. No. 4,695,098, issued Sep. 22, 1987 to Paurat et al describes an excavator for continuous strip mining of minerals. The ""098 excavator comprises a track drive, a digging unit with at least one digging roller and a connected conveyor for moving raw ore. While the ""098 patent discloses a suitable apparatus for moving raw ore the ""098 does not teach or suggest the claimed subject matter of the present invention, e.g., an apparatus and method that does not rely on sunlight or warm weather for killing weed pests.
U.S. patent Publication Ser. No. 2002/0018697, published, Feb. 14, 2002 to Vinegar et al describes a soil remediation system to remove or reduce chemical contaminates within soil particularly after a spill of a hydrocarbon, e.g., an oil mixture. The ""697 publication discloses heating elements in direct contact with soil to vaporize contaminants such as oil and other chemicals. Once vaporized the contaminants may be directed from the soil to a treatment facility through a manifold and piping made of a polymeric material. Thus, the ""697 publication is directed to different subject matter from that of the present invention and does not teach or suggest the pasteurization of a top soil for rendering the top soil particularly suitable for planting a fresh crop therein as claimed in the present patent application.
U.S. Pat. Nos. 5,190,405, 5,318,116, and 6,485,232 both issued to Vinegar et al also disclose the application of a thermal heating process to facilitate the removal of chemical contaminants from the ground. Neither the ""405, ""116 nor ""232 teaches or suggest the pasteurization of a top soil for rendering the top soil particularly suitable for planting a fresh crop therein as claimed in the present patent application.
Other U.S. patents disclosing some aspect of handling or treating soil, but which do not teach or suggest a top soil pasteurization apparatus and method of the present invention, include U.S. Pat. Nos. 4,348,135, 4,741,388, 5,012,795, 5,154,466, 5,221,827, 5,229,583, 5,233,164, 5,244,310, 5,322,115, 5,482,402, 5,484,985, 5,499,685, 5,586,213, 5,656,239, 5,674,424, 5,937,934, 5,975,799, 6,195,954, and 6,413,399.
Foreign patents disclosing some aspect of handling or treating soil, but which do not teach or suggest a top soil pasteurization apparatus and method of the present invention, include Japanese Patent No. 2001-269067, and W.I.P.O. Patent No. 02/094464 A2.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus a top soil pasteurization apparatus and method for obtaining improved crop yields solving the aforementioned problems is desired.
The present invention is an apparatus and method for killing weed pests and soil-borne plant pathogens that does not rely on sunlight or warm weather. More specifically, a top soil is artificially pasteurized thereby rendering the top soil particularly suitable for planting a fresh crop therein.
In one embodiment of the present invention a top soil heat treatment apparatus for pasteurizing a top soil comprises a housing; a soil heater; and a first soil mover, such as a helical screw, adapted to contact a top soil with the heat source in order to pasteurize the top soil, whereby the top soil heat treatment apparatus is capable of pasteurizing a top soil in order to improve potential crop yields. The soil heater is adapted to use any suitable heat energy source well known in the art of heating such as latent heat of condensation of steam driven through the soil heater. Exhaust gases may also be driven through the soil heater, e.g., hot exhaust gases from burning charcoal, wood, or diesel.
In another embodiment of the present invention, a method is provided to produce a pasteurized top soil particularly suitable for planting a crop therein. The method comprises the step of transferring heat energy from a soil heater to the top soil in order to produce the pasteurized top soil. The pasteurized top soil has a substantially reduced capability of growing weeds and an enhanced capability of growing a crop planted therein.
Accordingly, it is a principal object of the invention to provide a top soil heat treatment apparatus and method for pasteurizing a top soil.
It is another object of the invention to provide an apparatus and method for producing a pasteurized top soil suitable for planting a crop.
It is an object of the invention to provide a top soil heat treatment apparatus and method that can be used to pasteurize a top soil even during dull or cold weather.
It is a further object of the invention to pasteurize a top soil in a significantly shorter time span than the traditional soil solarization process.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.